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That is likely due to that ViewEngine is not caching "no hits", the consequence is that each call that does not match template will go through each view engine and often through all VPPs as well (since view engine locates files through VPPs). We have fixed this in CMS 7.5 and it will also be included in an upcoming patch 5 for CMS7. ASP.NET MVC also have a similar fix for this in MVC 5.
Another thing that is important when running MVC is to make sure debug=false on compilation section in web.config. This is since ASP.NET MVC will not cache hits either if you run in debug mode.
We have huge performance issues with those pages where we have enabled on-page eidting with the help of PropertyFor. Have realised that the ProertyFor is built on top of DisplayFor and hence the performance issues as per the discussion http://stackoverflow.com/questions/11758338/find-displaytemplates-speed. Any one got any ideas how to get rid of the performance issues while on-poage editing is enabled?